1. **State the problem:** We need to find the mean (average) price of the wireless headphones given the data set: 30, 50, 60, 70, 70, 70, 70, 80, 80, 90, 100, 100. 2. **Formula for the mean:** The mean is calculated by summing all the data points and then dividing by the number of data points. $$\text{Mean} = \frac{\text{Sum of all data points}}{\text{Number of data points}}$$ 3. **Calculate the sum:** Add all the prices: $$30 + 50 + 60 + 70 + 70 + 70 + 70 + 80 + 80 + 90 + 100 + 100 = 850$$ 4. **Count the data points:** There are 12 prices in total. 5. **Calculate the mean:** $$\text{Mean} = \frac{850}{12}$$ 6. **Simplify the fraction:** $$\text{Mean} = \frac{\cancel{850}}{\cancel{12}} = 70.8333...$$ 7. **Interpret the result:** The mean price is approximately 70.83. **Final answer:** Mean: About $70.83